Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to a cushioning device intended
primarily (but not exclusi~ely) for use as a trampoline.
Traditionally, a trampoline comprises a relatively
large rectangular sheet of canvas or the like supported by springs
from a rigid rectangular frame having support legs at its
corners. The canvas sheet provides a relatively large exercise
area, allowing the trampoline to be used for gymnastic exercises.
The beneficial effects of trampoline exercising have long been - -
recognized, but generally a high degree of skill and physical
fitness is required for a person to be able to effectively use
a trampoline. It has also been recognized that relatively
simple bouncing exercises on a trampoline can nevertheless form
an effective part of body toning programmes.
Small circular trampolines have been proposed for use
by individuals following a body toning programme. These
trampolines have a rigid circular frame of relatively small
diameter (four or five feet) from which a circular sheet of
canvas or the like is suspended by springs. Despite their
relatively small size, these trampolines are still quite cumber-
some and are not readily portable.
An object of the present invention is to provide animproved cushioning device which, according to one embodiment
of the invention, takes the form of a trampoline designed
primarily for use by an individual in performing bouncing or
jumping exercises.
The trampoline provided in accordance with this
preferred embodiment includes a hollow inflatable annulus
extending about an axis and defining respective end planes
,, ~
generally normal to said axis, whereby the annulus can be
supported on a horizontal surface in one of said planes
with its said axis generally upright. ~eans supported by
said annulus and providing an exercise surface extends
across at least part of the central opening of the annulus
at a spacing from said one plane. The annulus is capable
of resiliently cushioning impacts resulting from a person
jumping on said surface, and of causing said surface to
rebound subsequent to each impact.
According to an alternative embodiment of the
invention, the device may be used as a seating unit.
More broadly, the invention provides a cushioning
device which includes a hollow inflatable annulus of the
form defined above.
lS A primary advantage of a cushioning device of the
form provided by the invention is that it can be made
readily collapsible by deflating the annulus for ease of
transportation and storage. Also, the degree of cushioning
provided can be controlled by inflating the annulus to an
appropriate extent.
In order that the invention may be more cleariy
understood, reference will now be made to the accompanying
drawings which illustrate a number of preferred embodiments
of the invention by way of example, and in which:
Fig. 1 is a perspective view, partly broken away,
of a cushioning device intended for use as a trampoline
according to a preferred embodiment of the invention;
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Fig. 2 is a plan view corresponding to ~ig. 1;
Fig. 3 is a sectional view on line III-III of
Fig. 2;
Fig. 4 is a plan view corresponding to Fig. 2 but
with the mat of the trampoline removed;
Fig. 5 is a sectional view on line V-V of-Fig. 4;
and,
Figs. 6 to 15 illustrate alternative embodi-
ments of the invention and will be more particularly
described later.
Reference will first be made to Figs. 1 to 5
in describing a trampoline provided in accordance with a
preferred embodiment of the invention. The trampoline
includes a hollow inflatable annulus denoted 20 which
supports two mats 22 and 24 providing respective exercise
surfaces of the trampoline. In Figs. 4 and 5, the mats
have been omltted in order to show details of an outer nylon
net indicated at 26 ~by which the mats are supported), and
an inner net 28 of annular form which closely surrounds the
annulus and provides means for limiting radial expansion
of the cross-section of annulus 20 (see later).
Referring primarily to Figs. 2 and 3, it will be
seen that annulus 2G extends about an axis 30 and defines a
respectlve end planes 32 and 34 generally normal to the axis.
The annulus can be supported on a surface coincident with
either one of the planes 32 or 34 and with axis 30 generally
upright. In other words, the annulus is reversible and can
lie on either side with its opening facing upwardly. Two
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mats are provided so that the trampoline can be used either
way up. The two mats may have different surface charac-
teristics. For example, mat 22 could be a plain mat while
mat 24 might have an outer (exercise) surface covered with
an array of small protuberances designed to exert a "massaging"
effect on the feet of person using the trampoline. However,
in this particular embodiment, the two mats are the same and
are both formed from interwoven polypropylene fibres. The
mats are both secured to the supporting outer net 26 by
adhesive, although other fastening methods may be used (see
later).
A mat made of woven polypropylene fibres has been
found to be particularly suitable in this embodiment of the
invention because it is pervious to air. Thus, the particu-
lar trampoline shown is designed to use a relatively largediameter mat (as compared with the diameter of annulus 20)
and to permit air to pass through the mat as it moves up
and down in use. If the mat were not pervious to air, a
"piston" effect would occur and the air trapped below the
mat would severely inhibit up and down movement of the
mat. Of course, in an alternative embodiment, the trampo-
line could be designed to use an air-impervious mat, for
example, by making the mat smaller or by providing a
support for the annulus which would allow air to escape
outwardly around the bottom of the annulus.
The annulus itself is capable of resiliently
cushioning impacts resulting from a person jumping on
either of the mats 22 and 24 and of causing the relevant
mats to rebound subsequent to each impact. In this embodi-
ment, the annulus is made of butyl rubber and has an
outside diameter of 44 inches and an inside diameter of
24 inches. The annulus is of circular cross-section of
10 inches diameter. In Fig. 2 a valve for inflating the
annulus is indicated at 36. In another embodiment, the
valve could be designed to be stowed within the annulus or
otherwise disguised, for example, in a carrying handle at the
external diameter of the annulus. It is preferable for the
annulus to be inflatable and deflatable so that the trampo-
line can be collapsed for ease of transportation and storage,
although within the broad scope of the invention, the annulus
could of course be permanently inflated.
Referring now primarily to Figs. 4 and 5, the two
nets 26 and 28 are made of nylon filaments fused together
ln a crlss-cross configuration defining squares with 1 inch
sides. Parts only of the two nets are shown in Fig. 4 for
ease of illustration but in fact both nets are complete
as shown in Fig. 1. Net 26 completely encloses the annulus
and is fitted relatively tightly therearound. It is formed
from an appropriate length of net which is seamed into a
tube with and one end of which is closed by tying the net.
The net is then draped over the annulus and the other end
of the tube is tied to a retaining ring indicated at 38
in Fig. 4. The annulus can then be inflated until the
required tension is obtained in net 26. Finally, the
two mats 22 and 24 are secured to the respective sides
of the outer net.
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The inner net 28 is of annular form and is
shaped to closely fit around and enclose the annulus itself.
The net is formed around the annulus into a tube by wrapping
a generally annular shaped net section around the annulus
and securing together the inner and outer circular edges of
the annular net around the inner diameter of annulus 20.
This can be done by securing the edges together using suita-
ble adhesive or by providing buttons or other projections
on one edge which are engaged through the net along the
opposite edge. In any event, the inner net 28 fits snugly
around the annulus and has the effect of limiting radial
expansion of the cross-section of the annulus; that is, the
dimension indicated by arrow D in Fig. 5.
In practice, it has been found preferable to
provide some means such as net 28 for restricting inward
radlal expansion of the annulus ~that is, expansion which
would have the effect of reducing the internal diameter of
the annulus) whlle the annulus is being inflated. Such
expansion would have the effect of closing the central
opening of the annulus and thereby reducing the area which
will be available for bouncing. Thus, when the annulus
expands during inflation, it will eventually begin to
tension the outer net and in fact the intention is that
the annulus will be inflated until the outer net is tensioned
to the extent appropriate for the required characteristics
of the trampoline. Typically, the internal pressure of
the annulus might be in the range 4 pounds to 9 pounds per
square inch but this will depend on the resiliency of the
material from which the annulus is made and on the personal
.
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preference of the user. In any event, as the annulus begins
to tension the outer net, the resistance provided by that
net will have the effect of tending to cause the annulus
to expand inwardly as inflation continues~
It may be possible to limit inward expansion
of the annulus by using a specially designed annulus, for
example, one which has walls which are thicker around the
~nternal circumference of the annulus than around the outer
circumference. However, this form of annulus may be expen-
sive to manufacture and, for this reason, it may be preferred
to use an annulus having uniform wall thickness. Inward
radial expansion could then be controlled by a rigid inner
"hub" inside the annulus (see Figs. 9 and 10) but this has
the disadvantage that the annulus is not then completely
collapsible. Another possibility would be to provide
rigid rings extending around the end circumference of the
annulus, but again the problem of non-collapsibility remains.
It has been found preferable to control inward
radial expansion of the annulus by limiting radial expansion
of the annulus cross-section (dimension D in Fig. 5) such
as the inner net 28. In this way, it has also been found
possible to exercise some control over the "bounce" provided
by the trampoline and prevent it from becoming too soft.
Thus, it may not be possible to control the resiliency and
"bounce" of the trampoline entirely by varying the inflation
pressure of annulus 20. If the pressure is increased to
reduce the resiliency, the trampoline becomes 'Ihard'' and
1~4(~960
g
"lifeless". Conversely, if the pressure is reduced too far
the annulus becomes too soft and the trampoline may tend
to "throw" a person who jumps anywhere but directly in the
centre of the trampoline; in other words, the trampoline
becomes unstable.
Net 28 has been found to provide a particularly
expedient means for limiting inward expansion of annulus
20 but other means may alternatively be used; examples of
such other means will now be described with reference to
Figs. 6 to 10.
Figs. 6, 7 and 9 are plan views showing three
alternative means which may be employed to prevent inward
radial expansion of the annulus of a cushioning device of
the form provided by the invention. Figs. 8 and 10 are
cross-sectional views taken respectively on lines VIII-VIII
of Figs. 7 and on line X-X of Fig. 9.
In each of Figs. 6 to 10, the annulus itself
is generally denoted by reference numeral 20. In the
embodiment of Fig. 6, the annulus is wrapped by straps 40
of a material capable of stretching in one direction only
(for example~a knitted material having inextensible filaments
extending in one direction). The material is arranged so
that the straps 40 are inextensible in the direction extend-
ing circumferentially around the cross-section of the
annulus but can stretch in the circumferential direction of
the annulus. In this way, the annulus can grow radially
outwardly while the cross-section of the annulus remains
substantially constant. The straps 40 may be formed from
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-- 10 --
a continuous len~th of material spirally wound around the
annulus or individual straps may be used.
It will of course be understood that an outer
net or other expedient will be used externally of the straps
40 but has been omitted for clarity of illustration.
Referring now to Figs. 7 and 8, in this embodiment
expansion of the cross-section of the annulus is controlled
by a "glove" generally denoted by reference numeral 42. This
glove is made of a material which is substantially inextensible
and is shaped to enclose annulus 20. The glove is formed
with a series of slits or openings, some of which are indi-
cated at 44, which allows the glove to have an external
circumferential dimension greater than its internal circum-
ferential dimension sufficient to fit snugly around annulus
20. For ease of illustration, only some of the slits 44 have
been shown in Fig. 7 but it will of course be understood that
the slits will extend right around the glove. A zip fastener
46 extends around the inner circumference of glove 42 and
provides a means by which the glove may be fitted to and
removed from the annulus. In other embodiments, zip fastener
46 could of course be replaced by snaps or other fasteners.
Figs. 7 and 8 also illustrate an alternative
method by which the nets providing exercise surfaces may
be supported from annulus 20. While this featuxe has been
specifically illustrated in conjunction with the glove 42,
it is to be understood that it may be used with other
forms of inner expansion control means. In this embodiment,
only one net is shown and is indicated by reference numeral
~14~ 60
48. The mat is su~pcrted by a plurality of straps 50 each
of which has an inner end sewn to mat 48 and which extends
radially outwardly of mat 48 and around annulus 20. At
the underside of the annulus as seen in Fig. 7, the straps
may be sewn to a second similar mat or to some other form
of anchoring means. Alternatively, the straps could extend
right around below the annulus and be attached ~o mat 48 at
the opposite ends. In the particular embodiment illustrated
in Fig. 7, it is to be noted that the straps 50 are specifi-
cally positioned over the slits 48 in the glove 42 so thatannulus 20 can to some extent expand through the slits and
act directly on the straps 50 for tensioning mat 48.
Figs. 9 and 10 illustrate a further alter~
native embodiment in which inward radial expansion of
annulus 20 is prevented by a rigid inner hub 52 around
which the annulus extends. It will be noted from Fig.
10 that the hub 52 is of arcuate shape in cross-section
so as to conform generally to the curvature of annulus
20. The annulus is merely placed around the hub and
inflated and i6 not secured to the hub.
The particular form of the trampoline provided
by the invention has many advantages compared with prior
art trampolines including collapsibility and ready porta-
bility. The characteristics of the trampoline can be
readily varied at will by varying inflation of the annulus.
In addition, it has been found in practice that the tramp-
oline provides a "ride" which is particularly pleasing.
Not only does the inflated annulus provide cushioning but
.,
114~960
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the particular design of the tr~mpoline provides for added
resiliency which has been found to gi~e the user a "floating"
feeling and be particularly useful in body toning e~ercises.
Referring particularly to Fig. 3, it will be appreciated
5 that an impact downwardly in the direction of arrow A on
to mat 22 will have the effect not only of partially com-
pressing the annulus, but the tension forces engendered in
the upper surface of the outer net 26 at the time of impact,
will cause the annulus 20 to tend to "roll" inwardly as
lO indicated by arrow B. In other words, the annulus will not
only be compressed axially, but will also be torsionally
stressed or "rolled" inwardly which will have an additional
effect on the "bounce" of the trampoline. When the user
reaches the bottom of the bounce both the air pressure within
15 the annulus and the resilient nature of the walls of the
annulus will cause the components of the trampoline to tend
to restore towards their original conditions providing for
a rebound effect on the user.
Reference will now be made to Figs. 11 to 15 in
20 describing further features of the invention. Fig. 11 is
a perspective view of a stand which may be used in conjunc-
tion with a cushioning device of the form provided by the
invention; in Figs. 12 and 13, the device and stand are
shown in use together forming a seating unit, while in
25 Figs. 14 and 15 the stand is used as a support during use
of the cushioning device as a trampoline. In each of Figs.
12 to 15, the cushioning device is generally indicated by
reference numeral 54 and the stand is denoted as 56.
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Referring first to Fig. 11, the stand has a three-
legged form generally similar to an easel and comprises a
front frame 58 which is generally of inverted U-shape and
which defines the two front legs of the stand. A third,
telescopic leg extends downwardly from the top of frame 58
and is denoted 60. Hand grips 62 are provided on either
side of the point of attachment of leg 60 to frame 58.
These hand grips may be omitted where the stand is used
solely as part of a seating unit. A nylon cord 64 is secured
between the legs of the stand for controlling their spread.
Two short arms 66 and 68 protrude forwardly from the respect-
ive legs of frame 58 and a sling 70 extends between the
arms and forms a support for the cushioning device 54 as
best shown in Figs. 12 and 13. In the embodiment of Figs.
14 and l5, these arms 66 and 68 and slings 70 are omitted.
Referring to Figs. 12 and 13, it will be seen
that the cushioning device 54 is supported on sllng 70
against the legs of frame 58. The cushioning devlce itself
is essentially of similar form to the device as shown in
Figs. 1 to 5 in that it comprises an annulus 20, an outer
net 26, and an inner net 28. The device has an inner mat
22 only and the device is placed so that the mat 22 is
disposed at the side of the device which is in contact
wlth stand 56. The portion of the outer net 26 at the
opposite side of the device is relaxed and hangs loosely
inside the space at the centre of annulus 20 and is indicated
by reference numeral 26a in Fig. 13. This relaxed portion
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1~4~:)960
of the net provides a "pocket" in which a person can sit,
whereby the cushioning device and stand form a seating unit.
Relaxation of the outer portion 26a of net 26 is
possible because a tension control band indicated at 72 is
incorporated in the outer net. This band takes the form
of a wire or cord woven into the outer net and tightened
about annulus 20 so that the portion of net 26 which
carries mat 22 cannot pull around the annulus while the
outer portion 26a can be relaxed. Tension in this outer
portion of the net is released by detaching the net from
the retaining ring 38 (Fig. 4). In this embodiment, the
ring will take the form of a length of cord or rope which
can be simply released to relax the outer portion of the
net.
Figs. 14 and 15 are side and plan views respect-
ively showing the stand 56 (without the arms 66 and 68 or
81ing 70) ln association with a trampoline 54 of the form
provided by the invention. The trampoline is placed between
the two front legs of the stand and the person using the
trampoline can grasp the stand at the position of the hand
grips 62 and use the stand as a support. It is thought
that this facility of using the stand as a support will be
particularly useful for people learning to use the trampoline
or for people havlng a physical disability. For example,
the stand/trampoline combination could be used as a rehabi-
litation apparatus for people recovering from injuries.
It will of course be appreciated that the preceding
description relates to specific embodiments of the invention
3960
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and that many modifications are possible within the ~road
scope of the invention (in addition to or instead of the
modifications referred to above). For example, the particular
materials and dimensions referred to are given merely by
way of example and may vary in practice. The annulus may be
made of any appropriate material having a resilient memory.
In the embodiments described with reference to the drawings,
the cushioning device is referred to as having two mats (22
and 24) and reference is also made to the possibility of
using a single mat only. In another embodiment, the mats
could be omitted entirely (for example, where the cushioning
device is to be used as part of a seating unit). Where the
mats are omitted and the device is to be used as a trampo-
line, the outer net or equivalent may itsélf provide the
exercise surface(si of the trampoline. Where one or more
mats are provided, they need not be necessarily secured
to the outer net by adhesive as described above. Each mat
could ln fact be made as two layers positioned on respect
of the opposite sides of the outer net and stitched together
through the net. Another possibility would be to clip the
mat onto the net; in this event, the mat could be designed
to be reversible. Where a single mat is provided, it may
be desirable to provide a movement control band such as
that indicated in ghost outline at 74 in Fig. 3 to prevent
the annulus "rolling" inside out when the top mat (22) is
subjected to impacts in the direction of arrow A.- This
movement control band may simply take the form of a sub-
stantially inextensiblé cord or rope woven into the inner
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net 28.
In describing Fig. 2, reference was made to a
valve 36 for inflating the annuIus. It will of course
be understood that the position of the valve may vary.
Where the annulus is completely enclosed in an open woven
material, the valve can be placed on the outer circumference
of the annulus. Alternatively, if access is available to
the inner circumference of the annulus, the valve may be
placed on that circumference, for example, midway between
the mats. In any event, the valve should be accessible
so that the internal pressure of the annulus can be varied
when the cushioning device is in use.
It should finally be noted that reference in this
application to an "annulus" is to be construed broadly
as lndicatlng generally a closed geometric figure. In
other words, the "annulus" need not be strlctly circular.
For example, an oval annulus could be used or the annulus
could have the general shape of a rectangle with rounded
corners.
